(1) Field of the Invention
The present invention relates to enhanced convective cooling resulting from adding a U-shaped divider rib dividing a plurality of cooling fluid channels in a serpentine cooling passage.
(2) Prior Art
Vanes currently used in gas turbine engines use a three pass serpentine cooling passageway 10 such as that shown in FIGS. 1 and 2 to convectively cool a mid-body region of the airfoil 11. Cooling fluid enters the passageway 10 through a fluid inlet 12 and travels through the inlet channel 14, then around a first turn 16 into an intermediate channel 18, then around a second turn 20, and through an outlet channel 22. Heat transfer tests have shown that this configuration can be inadequate and cooling losses may be encountered due to poorly developed flow structure in the channels 14 and 18 and large regions of flow separation downstream of the first turn 16, extending almost to the second turn 20. These issues can be attributed to both the low flow rate per unit flow area, and to the very low aspect ratio in the channel 18 with long rough walls and short divider walls.
There is a need for a cooling passageway for the airfoil portion that has an improved flow structure and better heat transfer properties.